This invention relates to an optical sensor for use in applications wherein accurate determination of the contours of an object are important. Many industries require precision in determination of a position of an object that passes on a conveyer or on some other moving platform in order to accurately determine the dimensions of the object and detect any non-compliance with a "master image." For example, copy machines and laser printers need to accurately track the position of the paper in its path through the machine, and to make sure that the printed image is placed at a precise location on the piece of paper. The same is true for mass printing operations, wherein newspapers, magazines and other paper products are developed. To achieve this purpose, various devices have been proposed, some of them utilizing optical sensors to perform the above operations.
The present invention relates to a type of sensor which utilizes reflected optical flow for determination of the precise parameters of an object, as well as accurate printing in the desired area of the paper sheet.